1. Field of the Invention
The present invention relates generally to improvements in manure spreaders and more particularly is directed to an improved mechanism for spreading and distributing material stored in the spreader.
2. Description of the Prior Art
Manure spreaders generally consist of an open-end spreader box into which material, such as manure, is loaded for subsequent unloading and spreading, a conveyor within the spreader box for advancing the load of manure rearwardly toward the open end and a beater mechanism located at the open end of the spreader box for spreading and distributing manure stored therein over the ground. These individual components of the manure spreaders have been known and used for almost a century. Many necessary and valuable improvements have been made on the respective component parts throughout this time, especially improvements relating to the spreading and distributing beater mechanism.
One of the early manure spreader constructions is shown and described in U.S. Pat. No. 309,987, granted to Smith on Dec. 30, 1884. The spreader of this patent employs a beater mechanism comprised of two vertically spaced apart beaters rotatably mounted and transversely disposed in the open end of the spreader box. Each beater comprises a cylindrical drum having rows of spiked teeth projecting outwardly from the periphery of the drum. An apron conveyor conveys the manure rearwardly to the spiked toothed drums which are adapted to be rotated in opposite directions. The manure passes between the spiked-tooth drums and is spread onto the ground in a width generally limited to the width of the drums.
Various improvements were made to these early spreaders, one of which being directed to the spread width of the spreader. An example of such an improvement is shown in U.S. Pat. No. 1,313,595, granted to Hartsock on Aug. 19, 1919, wherein a distributor beater was mounted rearwardly of the spiked-tooth beaters. The distributor comprises a plurality of blades so arranged that upon rotation thereof the manure was spread a width greater than the width of the spiked-toothed beaters. This arrangement is commonly referred to today as a "wide spread" beater.
Although the spiked-tooth beater spreader with the wide spread attachment experienced much success, one disadvantage was the inability of this type of spreader to effectively spread fine materials. One solution was proposed in U.S. Pat. No. 1,820,528, granted to Claar on Aug. 25, 1931. Claar attached flat plates across the spiked teeth to form a paddle wheel configuration thereby converting the spreader for use with fine pulverized material, such as lime.
Another disadvantage of the spiked-tooth beater spreaders were their inability to handle a compacted material, such as, material having a pasty consistency or material having large lumps dispersed therein. Thus, the paddle-type beater was introduced. The paddle beater comprised a series of paddles having a generally flat body portion with notched outer peripheral edges and arranged on a rotatable shaft such that upon rotation thereof, the notched paddles would aggressively engage and scoop up the material, tear and shred the material into smaller particles and then distribute the same rearwardly of the spreader. The paddle-type beater can be found in manure spreaders having a single beater arrangement, such as in U.S. Pat. No. 3,632,050 granted to Lee on Jan. 4, 1972 and also in double beater spreaders as shown by U.S. Pat. No. 3,722,307 granted to Campbell on Mar. 27, 1973.
Although, the paddle type beater spreader was an improvement over the spiked-toothed beater spreaders, especially in its ability to handle all types and consistencies of material, it had other limitations. Such limitations derive from its inability to achieve a wide spread pattern and uniform distribution of material over the ground in an even thin layer.